The invention relates to an apparatus for lifting planiform articles, especially sheet-like (intermediate) layers, off an underlayer, for instance off (blank) stacks of a pallet or the like, by means of a suction lifter which can be placed on the top side of the (intermediate) layer with suction bores.
Articles are often stacked on pallets in tiers, with a thin sheet-like intermediate layer being arranged between the individual tiers. This intermediate layer or separator may be made of cardboard, in particular corrugated cardboard, or sometimes of a synthetic material.
The tiers may consist of individual articles arranged side-by-side in each tier, or of (small) stacks of sheet-like articles. An important example is the arrangement of pre-fabricated blanks of thin cardboard for producing packs, especially hinge lid (cigarette) packs. The specially designed blanks are assembled in stacks of, for instance, one thousand blanks and are placed on a pallet side-by-side as a tier for transport and storage. The above-mentioned intermediate cardboard layers are located between the tiers of a group of tiers stacked above one another.
Usually, automatic depalletizers are used for unloading the pallets on site. These may be constructed in different ways. In any case, there still remains the problem of removing the intermediate layers after unloading a tier.
Heretofore, the intermediate layers have been lifted off the tiers of the pallets mainly by hand. There are, however, automatic depalletizers known in the packaging industry which are equipped with a suction lifter for engaging the top side of stacked articles.
The (manual or mechanical) removal of the intermediate layers involves the risk of the articles of the tiers being displaced relative to one another. This is particularly the case when the tiers are formed of blank stacks, since the latter have a low dead weight and can be easily shifted relative to one another. There is also the risk of the upper blanks of the blank stacks being lifted off together with the intermediate layer.